There are many different types of water treatment systems, each with its own unique contaminant removal efficacies. Knowing and understanding the different types can help you choose the right one for your needs and preferences.
Reverse Osmosis is an effective way to remove many dissolved particles from water. This includes salts, organics, proteins and dissolved chemicals like chlorine, fluoride and aluminum that can cause health problems. Reverse osmosis systems also contain prefilters to remove contaminates that can clog the membrane. These prefilters are usually carbon and sediment filters, but they can include other filters depending on the model of system. Reverse osmosis can also remove a large number of dissolved minerals and metals including arsenic, barium, chromium, copper, iron, magnesium, manganese, nickel, nitrate, selenium, sodium, sulfate and zinc. It can also remove odor-causing substances, taste, color, and other pollutants.
Typically, activated carbon is used in adsorption applications to remove light pollutants from gases or vapors. It can be used in sewage plants to remove hydrogen sulfide or in air-conditioning units to filter breathing air. Adsorption involves a chemical reaction between substances and the surface of an adsorbent, using molecular attractions called van der Waals forces. Activated carbon has a high surface area and microporosity that allows it to adsorb molecules from gases or vapors. Activated carbons are available in both powdered and granular forms. Generally speaking, granular activated carbon (GAC) is more common in the water treatment industry because of its ability to be regenerated. However, some plant operators choose to use powdered activated carbon when they are lacking the infrastructure to install granular activated carbon.
Ultrafiltration is a pressure driven water purification process where water is forced through a semipermeable membrane that allows small water molecules to pass while retaining larger molecules. It removes most organic molecules, viruses, and a range of salts. It is used to produce potable water from seawater, sewage, and wastewater and is also useful for pretreatment of desalination or reverse osmosis systems. It can be applied to a wide range of applications including food processing, biotechnology, and chemical processes. This technology has gained widespread use in industrial applications where it is an effective way to remove particulates, bacteria, and other macromolecules. It is also effective for reducing the volume of waste that requires treatment.
Sedimentation is a type of water treatment process that uses gravity to remove suspended solids. It is used to reduce water turbidity, a major cause of health concerns. It is also used to treat wastewater and initial water treatment for potable water. In order to make this process more efficient, clarification tanks are constructed using mechanical means for the continuous removal of solids that are deposited by sedimentation. These clarifiers include horizontal flow tanks, radial flow clarifiers, inclined plate tanks, solids contact clarifiers and ballasted sedimentation systems.